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CAS E REP O R T Open Access
Delayed intracardial shunting and hypoxemia
after massive pulmonary embolism in a patient
with a biventricular assist device
Thomas Weig
1*
, Michael E Dolch
1
, Lorenz Frey
1
, Dirk Bruegger
1
, Peter Boekstegers
3
, Ralf Sodian
2
and
Michael Irlbeck
1
Abstract
We describe the interdisciplinary management of a 34-year-old woman with dilated cardiomyopathy thr ee months
postpartum on a cardiac biventricular assist device (BVAD) as bridge to heart transplantation with delayed onset of
intracardial shunting and subsequent hypoxemia due to massive pulmonary embolism. After emergency surgical
embolectomy pulmonary function was highly compromised (PaO
2
/FiO
2
54) requiring bifemoral veno-venous
extracorporeal membrane oxygenation. Transesophageal echo cardiography detected atrial level hypo xemic right-
to-left shunting through a patent foramen ovale (PFO). Percutaneous closure of the PFO was achieved with a PFO
occluder device. After placing the PFO occluder device oxygenation increased significantly (Δ p

a
O
2
119 Torr). The
patient received heart transplantation 20 weeks after BVAD implantation and was discharged from ICU 3 weeks
after transplantation.
An increase in pulmonary vascular resistance in patients on BVAD can reopen a PFO resulting in atrial right-to-left
shunting and subsequent hypoxemia. The case demonstrates the usefulness of transesophageal echocardiography
examinations in the detection of this unexpected event. Percutaneous placement of a PFO occluder device is an
appropriate strategy to stop intracardiac shunting through PFO in fixed elevation of pulmonary vascular resistance.
Keywords: patent foramen ovale, hypoxemia, pulmon ary embolism, ventricle-assist device, heart transplantation,
septal occluder device
Background
In a literature review, few cases of atrial level right-to-
left shunt in patients with left ventricular assist devices
are described. All these cases were detected either
intraoperatively [1-3] or within the first postoperative
days [4-7] . We describe a case of delayed onset of atrial
level right-to-left shunt after massive pulmonary embo-
lism on biventricular assist device (BVAD) support.
Case Presentation
A 34 year old female patient was admitted to our hospi-
tal with dilated cardiomyopathy three months after birth
of her third child. She had a known history of familial
dilated cardiomyopathy. Recompensation was not
achieved despite maximum medical therapy and inser-
tion of an intra-aortic balloon pump. BVAD [Excor, Ber-
lin Heart, Berlin, G ermany] was implanted using a bi-
atrial cannulation technique as bridge to heart trans-
plantation. Perioperative transesophageal echocardiogra-

phy did not show a patent foramen ovale (PFO).
Postoperative recovery was immediate and the p atient
was discharged from the ICU on the third post operative
day.
Four weeks after device implantation the patient
developed fulminant pulmonary embolism despite thera-
peutic anticoagulation. Emergency surgical embolectomy
for massive pulmonary embolism was performed since
thrombolysis was not an option after recent implanta-
tion of an artifici al heart (Figure 1). Pulmonary fu nctio n
was highly compromised after embolectomy and veno-
venous extracorporeal membrane oxygenation (ECMO)
[Bio-Console, Medtronic, Minneapolis, USA] was
* Correspondence:
1
Department of Anaesthesiology, Ludwig-Maximilians-University, Munich,
Germany
Full list of author information is available at the end of the article
Weig et al. Journal of Cardiothoracic Surgery 2011, 6:133
/>© 2011 We ig et al; licensee BioMed Central Ltd. This is an Open Access article distribute d under the terms of the Creative Commons
Attribu tion License ( which permits unres tricted use, distribution, and reproduction in
any mediu m, provided the original work is properly cited.
established using a bife moral ven ous acce ss. Wean ing
from veno-venous ECMO was achieved over the following
week but after removal oxygenation failure reoccurred.
F
i
O
2
of 1.0 was necessary to achieve sufficient o xygen

satur ation (p
a
O
2
/F
i
O
2
54). Modification of ventilator set-
ting with adjustments of PEEP and peak inspiratory pres-
sure did not lastingly improve oxygenation.
Transesophageal echocardiography detected atrial level
intracardial shunting (Figure 2). There was no improve-
ment after application of inhaled pulmonary vasodilata-
tors. CT-scan after surgical embolectomy showed residual
emboli in the pulmonary vascular system. Invasive proce-
dures such as r e-embolec tomy, topical thrombolysis or
catheter fragmentation were considered as too harmful or
not effect ive. Since right heart function was secured eve n
with high pulmonary vascular resistance, percutaneous
placement of a PFO occluder device [Amplatzer PFO
Occluder
®
, AGA Medical, Plymouth, USA] was performed
(Figure 2, Additional file 1). Oxygenation increased signifi-
cantly after placement without change of respirator set-
tings (Δ p
a
O
2

119 Torr). Weaning from mechanical
ventilation was successful after 15 weeks.
After 5 weeks of therapeutic anticoagulation the resi-
dual embo li diminished and pulmonary vascular resis-
tance was measured at 184 dyne•s/cm
5
with activated
assist device and 160 dyne•s/cm
5
with deactivated assist
device.
Heart transplantation was performed 20 weeks after
implantation of the BVAD and 16 weeks after pulmonary
embolism and placement of the PFO occluder device.
Discharge from ICU was 3 weeks after transplantation.
Informed consent for publication was obtained from the
patient.
Discussion
The problem with PFO and left ventricular assist device
leading to atrial level right-to-left shunt with consecutive
hypoxemia i s well described [1-7]. PFO has an incidence
up to 27% in normal healthy a dults as well as in adult
cardiac surgical p atients [8,9]. If left ventricular as sist
device (LVAD) is activated, left atrial unloading leads to
a decrease in left atrial pressure [10]. Right atrial pres-
sure exceeds left atrial pressure and with PFO atrial
level right- to-left shunt occurs. Depending on the shunt
fraction hypoxemia may occur [11].
Therefore, intraoperative transesophageal echocardio-
graphy with colour Doppler imaging and contrast with

agitated saline i s highly recommended before cardiopul-
monary bypass and after LVAD activation [12,13]. Alter-
natively, manual occlusion of the pulmonary artery
shortly before activatio n of the LVAD by the surgeon
and transesophageal echocardiography studies as
described are performed [14]. If PFO is detected before
weaning from cardiopulmonary bypass, immediate
operative closure is recommended. If shunting is
detected after weaning from cardiopulmonary bypass,
delayed interventional closure after stabilization is pre-
ferred if oxygenation failure is tolerable, since failure of
the right heart in LVAD implantation or bleeding com-
plications due to coagulopathy after reapplied bypass
Figure 1 CT-Scan: A & B before surgical embolectomy. C & D directly after surgical embolectomy.
Weig et al. Journal of Cardiothoracic Surgery 2011, 6:133
/>Page 2 of 4
can deteriorate outcome [2]. PFO closure improved oxy-
genation in all known cases as it did in our patient.
Ther e is only one other case of delayed onset of atrial
level right-to-left shunt in patients on ventricular assist
device [15]. In this case report, atrial level right-to-left
shunt wit h hypoxemia occurred after replacement of the
valves of a LVAD [LVAS, Novacor, Salt Lake City, USA]
which had been implanted one year before. The man-
agement consisted of reduction of right atrial pressure
by conservative means.
Persisting el evation of right atrial pressure due to per-
sisting change of the pulmonary vascular resistance in a
patient with a BVAD has not been described. An etiolo-
gic reason for persisting elevation of pulmonary vascular

resistance can be massive pulmonary embolism as
described in our case. Our report is the first description
of a patient surviving massive pulmonary embolism
while on BVAD, followed by succ essful orthotopic heart
transplantation. To the best of our knowledge there is
only one other published case of pulmonary embolism
in a patient with a BVAD. This patient died shortly after
the event [16].
Emergency surgical embolectomy is recommended in
hemodynamic unstable patients with massive pulmonary
embolism in a facility with cardiac surgical capabilities
[17]. Catheter embolectomy should be performed in
absence of cardiothoracic surgical backup [17]. In our
case, thrombolysis was contraindicated. Therefore emer-
gency surgical embolectomy was the treatment of
choice. The reported median reduction of pulmonary
vascular resistance achieved by surgical e mbolectomy is
from 893 ± 443.5 dyne•s/cm
5
to 285 ± 214 dyne•s/cm
5
[18], a result that was achieved in our patient.
With regard to the planned heart transplantation,
chronic thromboembolic pulmonary hypertension would
have been an exclusion criterion.
Conclusion
Diagnostic transesophageal echocardiography must be
performed with relevant change in the hemodynamic
Figure 2 Transesophageal echocardiography: A & B before, C & D after patent foramen ovale closure with a PFO occluder device
[Amplatzer PFO Occluder

®
, AGA Medical, Plymouth, USA].
Weig et al. Journal of Cardiothoracic Surgery 2011, 6:133
/>Page 3 of 4
situation and recurring hypoxemia in patients with VAD
since increase in pulmonary vascular resistance can
reopen PFO resulting in atrial level right-to-left shunting
and consecutive hypoxemia.
Consent
Written informed consent was obtained from the patient
for publication of this Case r eport and any accompany-
ing images. A copy of the written consent is available
for review by the Editor-in-Chief of this journal.
Additional material
Additional file 1: Transesophageal echocardiogram. Transesophageal
echocardiogram before and after patent foramen ovale closure with a
PFO occluder device [Amplatzer PFO Occluder
®
®, AGA Medical,
Plymouth, USA].
Author details
1
Department of Anaesthesiology, Ludwig-Maximilians-University, Munich,
Germany.
2
Department of Cardiovascular Surgery, Ludwig-Maximilians-
University, Munich, Germany.
3
Department of Cardiology, Helios Klinikum
Siegburg, Siegburg, Germany.

Authors’ contributions
TW reviewed the case, conducted a review of the literature and drafted the
manuscript. TW and MI performed the echocardiographic studies and
participated in the design of the case report. RS and PB performed the
operation and intervention described. MD, LF and DB confirmed the
patient’s diagnosis and revised the manuscript, contributing important
intellectual content. All authors read and approved the final manuscript.
Competing interests
The authors declare that they have no competing interests.
Received: 19 August 2011 Accepted: 11 October 2011
Published: 11 October 2011
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doi:10.1186/1749-8090-6-133
Cite this article as: Weig et al.: Delayed intracardial shunting and
hypoxemia after massive pulmonary embolism in a patient with a
biventricular assist device. Journal of Cardiothoracic Surgery 2011 6:133.
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